stroke variety vs shoulder pain

Wanted to thank the fishes who commented on an earlier thread on why to add a little variety to your stroke in training.  I'd been developing a nagging ache/pain in both anterior deltoids and over the shoulder joint capsule/insertion.  Tried a couple 100 backstroke during W/U and C/D.  Really stretched out my painful area and pain is all but gone after just 2 sessions. 

These bits of brilliance are why I lurk here on BT.